Risks scales

The prevention plan, and in particular symbols and warnings on labels and packaging of a substance, will depend on this risk level. In order to make sense, the risk classification has to take into account the inflammability level of a substance, to be on a coherent risk scale and not the mere result of more or less unpredictable fluctuations, particularly those due to the choice of apparatus or working method. The aim of estimation is to be able to identify substances on a scale where their position directly indicates their level of inflammability risk. 

In closing this Chapter it can be seen that instability risk remains relatively easy to forecast, but more difficult to estimate on a risk scale. The approach that seems most suitable could consist in ... 

Burt and Stevenson (2009) and Burt et al. (2009) examined employees perceptions of organizational processes and how these are associated with their reactions to new employees. Perceptions of recruit and selection processes are discussed in Chap. 5, and perceptions of socialization and prestart training processes are discussed in Chap. 6. Both chapters note how a perception that organizational processes helps ensure safety can be associated with a lowering of risk perceptions, a decrease in behaviors which should ensure safety, and thus an overall increase in workplace safety risk. Scales used to measure perceptions of tmst in selection process, trust in induction processes, and employees reactions to new employees (compensatory behaviors) are published in the appendix of Burt et al. (2009). 

Issues which involve missing information but where that absence is obvious typically sit at the lower end of the risk scale. For example, when a system is completely unavailable this is clearly apparent and clinicians will automatically strive to obtain the information from elsewhere or delay making a clinical decision until the information is available. However, where information is unavailable but its absence cannot be detected, this will typically notch the clinical risk up a degree. For example, suppose an investigation result includes some important free text notes but these are omitted when reviewing the patient s clinical record. As not all results will contain free text notes there is nothing to prompt the clinician to call the lab, repeat the investigation or consult paper-based results. 

Rudolph JL, Salow MJ, Angelini MC, McGlinchey RE. The anticholinergic risk scale and anticholinergic adverse effects in older persons. Arch Intern Med 2008 168(5) 508-13. 

Lowry E, Woodman RJ, Soiza RL, Mangoni AA. Associations between the anticholinergic risk scale score and physical function potential implications for adverse outcomes in older hospitalized patients. J Am Med Dir Assoc 2011 12 (8) 565-72. 

Wilson s Risk Scale of Material Hazards (RISK) R 1 (reactivity stable at room temperature may be unstable at elevated temperatures) I 2 [inhalation TLV 101 to 500 ppm (vapor) or 1.1 to 10 mg/m (soUd)] S 3 (skin contact severe irritation tissue corrosion within short time period) K 0 (kindling will not bum) Genium s, 1999)... 

In connection with road traffic, with its special condition of self-determination of the rate of work, studies by Taylor [6-40] and Wilde [6-41] have indicated that there is an adequate awareness of the risk content in particular situations. Both authors carried out field experiments which showed that drivers regulate their behavior within the MME-system so that the risk they experience fluctuates only between narrow limits. Thus Taylor reported that drivers tend to increase the speed of the vehicle in situations in which low risk is perceived, and to reduce speed if the perceived risk increases again. The perceived risk was determined in these experiments using the psycho-physiological measure of the galvanic skin response. In a similar experiment Galton and Wilde [6-42] showed that the subjective risk was determined on the basis of a verbally formulated risk scale. The test route consisted of 11 sections with heterogeneous traffic... 

Semiquantitative methods are used to describe the relative risk scale. For example, risk can be classified into categories such as low, medium, high, or very high. The number of levels of risk can vary from (say) a to b. In a semiquantitative approach, different scales are used to characterize the likelihood of adverse events and their consequences. Analyzed probabilities and their consequences do not require accurate mathematical data. Semiquantitative assessment is useful especially if quantification of risk is difficult. At the same time, qualitative interpretation is too subjective. As already discussed, the risk graph (highly project dependent) discussed in Chapter 1 in conjunction with available guided risk nomogram or LOPA approach, is commonly used for this purpose. Here discussions wiU be mainly on the LOPA approach (LOPA wiU be dealt with separately later). 

Once the predicted flood risk (i f) and the acceptable flood risk (i f) are obtained, a measure of the flood risk level that is appropriate for the decision making under consideration can be formulated as a function of cost and further intangible losses. For instance, a risk scale C = /i f = 0 shows an optimum risk level. 

Note The score noted on the far right has three numbers to score each risk after countermeasures are in place. Once the assessment is completed then all scores are then added and matched to the Task Risk Scale at the bottom of the chart. 

Note Task risk scale The score for a risk is only determined once the countermeasures are followed 1 = no risk 2 = moderate risk 3 = high risk (other countermeasures must be found). ANY 3 must be addressed immediately before the rigging and hoisting can begin. 

At the lower end of the risk scale, a Broadly Acceptable Risk is nearly always defined. This is the risk below which one would not, normally, seek further risk reduction. It is approximately two or three orders of magnitude less than the total of random risks to which one is exposed in everyday life. 

Figure 18-9 shows the relation between the Contamination-index and the degree of contamination on an ascending risk scale of 1 to 5 of man s feeling. A good correlation is found between them. 

The problem is that risk doesn t come in convenient units like volts or kilograms. There is no imiversal scale of risk. Scales for one industry may not suit those in another. Fortunately the method of calculation is generally consistent and it is possible to arrive at a reasonable scale of values for a given industry. As a result lEC have suggested using a system of risk classification that is adaptable for most safety situations. We refer here to Annex B of lEC 61508 part 5 that provides risk classification tables. 

Although this first route was simple in concept, it proved slow in operation, difficult to scale up safely, and relatively uneconomical compared with the other routes. Denitration of the fibers, necessary to allow safe use wherever the fabrics may risk ignition, spoiled their strength and appearance. Nevertheless, Chardoimet earned and truly deserved his reputation as the Eather of Rayon. His process was operated commercially until 1949 when the last factory, bought from the Tubize Co. in the United States in 1934 by a Bra2iUan company, burned down. 

The development section serves as an intermediary between laboratory and industrial scale and operates the pilot plant. A dkect transfer from the laboratory to industrial-scale processes is stiH practiced at some small fine chemicals manufacturers, but is not recommended because of the inherent safety, environmental, and economic risks. Both equipment and plant layout of the pilot plant mirror those of an industrial multipurpose plant, except for the size (typically 100 to 2500 L) of reaction vessels and the degree of process automation. 

The most popular scheme among commercial companies is the assignment of a risk priority number (RPN) based on probabiUty of occurrence, detectabihty, and severity of a particular failure mode. The factors (Occ, Sev, and Det) are each rated on a 1 to 10 scale and then an RPN is based on the product of the three rating values. 

The need for a pilot plant is a measure of the degree of uncertainty in developing a process from the research stage to a hiU commercial plant. A modification to a weU-known process may go directiy from basic research work to design of a commercial plant using this approach for a brand new process risks a significant failure. Hence, one or more intermediate size units are usually desirable to demonstrate process feasibiUty as well as to determine safe scale-up factors. 

Scale-up is the process of developing a plant design from experimental data obtained from a unit many orders of magnitude smaller. This activity is considered successful if the commercial plant produces the product at plaimed rates, for plaimed costs, and of desired quaUty. This step from pilot plant to full-scale operation is perhaps the most precarious of all the phases of developing a new process because the highest expenses ate committed at the stages when the greatest risks occur. 

Economy of time and resources dictate using the smallest sized faciHty possible to assure that projected larger scale performance is within tolerable levels of risk and uncertainty. Minimum sizes of such laboratory and pilot units often are set by operabiHty factors not directly involving internal reactor features. These include feed and product transfer line diameters, inventory control in feed and product separation systems, and preheat and temperature maintenance requirements. Most of these extraneous factors favor large units. Large industrial plants can be operated with high service factors for years, whereas it is not unusual for pilot units to operate at sustained conditions for only days or even hours. 

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